1. Field of the Invention
The present invention relates to an information processing apparatus and a signal transmission method.
2. Description of the Related Art
Most mobile terminals typified by mobile phones and the like use a movable member for a connecting portion between an operation portion to be used by a user and a display portion on which information is displayed. An opening and closing structure of a folding mobile phone is typical of such a movable member. Furthermore, in addition to a call function and an email function, recent mobile phones are provided with a viewing and listening function for a video, an imaging function and the like, thus requiring the above-described connecting portion to be able to be moved in complicated ways according to purposes of the user. For example, in a case of using the viewing and listening function for a video, the user would want to turn the display portion toward himself and stow away the operation portion which is unnecessary for viewing and listening. Thus a structure is desired which would enable the orientation or position of the display portion to be easily changed according to the purpose, such as when the mobile phone is used as an ordinary phone, when it is used as a digital camera, or when it is used as a television receiver.
However, a large number of signal lines and power lines pass through the connecting portion between the operation portion and the display portion. For example, several tens of wires are connected in parallel in the display portion. Therefore, when a movable member capable of complicated movement as described above is used for the connecting portion, the reliability and the like of the wiring will decrease significantly. For this reason, technology has been shifting from a parallel transmission scheme to a serial transmission scheme to reduce the number of signal lines in the connecting portion. Of course, technological shifts for similar reasons are not limited to the field of mobile phones, and are occurring in the fields of various electronic devices for which complicated wiring is required. Moreover, an additional reason for serialization may be to reduce electromagnetic interference (EMI).
In the serial transmission scheme described above, transmission data is transmitted after being encoded by a specific scheme. As the encoding scheme, for example, the non-return-to-zero (NRZ) encoding scheme, the Manchester encoding scheme, the alternate mark inversion (AMI) encoding scheme, or the like, may be used. For example, JP-A-1991-109843 discloses a technology for transmitting data by using an AMI code, which is a representative example of a bipolar code. The patent document also discloses a technology with which a data clock is transmitted after being expressed by an intermediate value of a signal level, and the receiving side regenerates the data clock based on the signal level.